hi,
it sounds familiar..
For 1,
sum ph has internal coast setting menu..u have to enter u r curent balance once n your call charge per minute..rest ph will do as per idea..u have to do this when u refil u r account everytime..
For 2nd,
our customer(operator) provide an application (using sms on toll free num)as well as gprs based where we can provide our credit/debit card detail n recharge accordingly..application name-mchek ..
Br,
kamal